A color developer is lately provided as a concentrated solution product or powdery product in a unit of a plurality of separated parts packed in a kit form in order to reduce its weight or bulk in transport or from the viewpoint of its preservability.
The parts of the color developer kit are dissolved or diluted in water to be used as a color developer solution or as a color developer replenisher in an actual processing operation.
However, certain chemicals that constitute the kit have a problem that, even when stored as members of the kit, if the storage period is prolonged, when processing is made in a processing solution prepared by dissolving the kit, the chemicals may be unable to provide any expected characteristics.
On the other hand, with the recent prevalence of a minilab processing system, technological improvement of processors and associated equipment used therefor have been developed, particularly for an automated print-making process. For this reason, there are increasing cases where unskilled operators, such as part-timers having no expertize, are employed for the processing work, which result in lowering of printing yield.
The use of a color developer solution that is unable to provide any intended characteristics or kits different in the storage period brings about a badly loss of printing yield because of the difference in its developability, leading to inconsistent printing levels. Such a loss of the printing yield is of a vital importance affecting the very existence of the photofinisher.
Incidentally, with the recent tendency of shortening the photographic processing time or using less replenishment of processing solutions there has arisen a demand for a more concentrated kit than the conventional ones and long-term preservability improvement.
It has been found, however, that even such a highly concentrated kit still has a problem in its preservability and is unable to provide stable photographic characteristics. For example, where the kit is stored during summer or transported across the equator, a preservative contained in the kit becomes badly deteriorated and, when used for processing, produce very unstable photographic characteristics.
Accordingly, in respect of a concentrated color developer composition containing a preservative, there is a demand for developing a technique to provide stable photographic processability.